The Utah attorney general said the state was careful to tailor HB497 to reflect recent federal court opinions on other states' immigration enforcement efforts, but there are "one or two minor things they still have some heartburn over" that could be corrected by the Utah Legislature in its next session.

Shurtleff said he plans to continue to talk with federal authorities about "a few modifications" that could end the challenge.

The U.S. Department of Justice filed the lawsuit against Utah Tuesday over the law that took effect earlier this year. The federal lawsuit suit claims that HB497 is unconstitutional because it attempts to establish a state immigration policy.

"A patchwork of immigration laws is not the answer and will only create further problems in our immigration system," U.S. Attorney General Eric Holder said in a statement.

"The federal government is the chief enforcer of immigration laws, and while we appreciate cooperation from states, which remains important, it is clearly unconstitutional for a state to set its own immigration policy."

The lawsuit states that HB497 precludes state and local law enforcement officers in Utah from being able to respond to federal priorities, according to the lawsuit, and “will therefore disrupt the enforcement of federal immigration law.”

It will also “cause the detention and harassment of authorized visitors, immigrants and U.S. citizens, thereby further undermining exclusive federal control over the conditions of residence for lawfully admitted aliens and, potentially, a wide range of U.S. foreign affairs interests and commitments,” the lawsuit states.

Gov. Gary Herbert's general counsel was reviewing the lawsuit, said the governor's spokeswoman, Ally Isom.

"The Legislature worked hard to craft a piece of legislation that would withstand constitutional scrutiny, and we're confident the courts will rule in our favor," Isom said.

Initially modeled after an Arizona law, HB497 requires police to verify the immigration status of people arrested in Utah for felonies and class A misdemeanors and those booked into jail on class B and class C misdemeanors. It also says officers may attempt to verify the status of someone detained for class B and class C misdemeanors.

The 30-page lawsuit seeks a judgment declaring three sections of HB497 "invalid, null and void."

It also seeks permanent and preliminary injunctions against the state of Utah prohibiting the enforcement of sections 3, 10 and 11 of the law. Section 3 refers to determining immigration status of an individual during a stop or arrest. Section 10 defines and establishes penalties for transporting or harboring "aliens" and Section 11 refers to arrests by police officers.

Tuesday's court action comes after several months of discussions on the new law between state and federal officials, including meetings in Salt Lake City and Washington, D.C. Justice Department officials expect that dialogue to continue, the agency said.

"So much for Shurtleff and the Utah Compact and HB116," said Ron Mortensen, co-founder of the Utah Coalition on Illegal Immigration. "They went back there and said, 'We've been nice guys so don't pick on us on this one.'

"It doesn't look like the Utah Compact and HB116 bought off the Obama administration," he said.

Rep. Stephen Sandstrom, R-Orem, sponsor of HB497, said he was disappointed by the filing of the lawsuit. He met with DOJ officials a few weeks ago and said he was "fairly encouraged" then that they would not go forward with the lawsuit because of differences between Utah's law and those that already have been challenged.

"They acknowledged there was a different spirit to the bill. It was more prudent and, at the same time, effective," Sandstrom said, blaming political pressure from the Obama administration.

Shurtleff has had a number of meetings with DOJ officials in recent months attempting to head off a lawsuit. He said recently, however, that it was likely that the federal government would intervene in the matter because it was under increasing pressure.

Along with HB497, state lawmakers also approved HB116 in the past legislative session that would establish a guest worker program for illegal immigrants. A group of conservative Republicans is working to repeal the law and replace it.

The ACLU and National Immigration Law Center filed a complaint in May on behalf of several individuals and organizations, including Utah Coalition of La Raza and the Latin American Chamber of Commerce. A temporary restraining order was issued to stop the law from taking effect in mid-May.

"Needless to say we're happy to see the DOJ has joined us," said Joe Cohn, ACLU of Utah interim legal director. "The DOJ has sent a strong message that states should not attempt to try to turn federal immigration policy into state legislation."

Utah is the fourth state the federal government has sued over illegal immigration law. The others are Arizona, Alabama and South Carolina.

And, said Cohn, the Justice Department "has a strong record, so far, of prevailing."

The lawsuit takes note of the number of states that have "attempted to encroach upon the federal government's exclusive authority to regulate immigration."

"This patchwork of inherently contradictory immigration regimes would result in the divergent treatment of aliens across the United States and interfere with the United States' ability to speak with one voice in this highly sensitive area," DOJ attorneys wrote.

Salt Lake immigration attorney Mark Alvarez said he had expected the federal government to intervene in the matter. "The state law clearly infringes on federal prerogative," he said.

Moreover, the state law burdens Immigration and Customs Enforcement with additional duties and "distracts ICE from its fundamental priorities," Alvarez said.

He predicted the matter would be mired in federal court for "a very long time."

"I'm just glad the Department of Justice saw fit to join the suit," he said. "In fact, I hoped for it."

The Department of Justice, in a press release, states that it “will not hesitate to take the legal action necessary to vindicate the important federal interests in this matter before these laws go into effect” if Utah failed to comply with federal law in this area.

The lawsuit itself states that, “In pursuing a ‘Utah solution’ through the Utah immigration statues, the state of Utah has explicitly disregarded Congress’ policies and objectives in favor of its own."